A double-layer composite electrode based on Ba0.5Sr0.5Co0.8Fe0.2O3-delta + Sm0.2Ce0.8O1.9 (BSCF + SDC) and BSCF + SDC + Ag was investigated to be a promising cathode and also anode for the electrochemical oxygen generator based on samaria doped ceria electrolyte. The Ag particles in the second layer were not only the current collector but also the improver for the oxygen adsorption at the electrode. a.c. impedance results indicated that the electrode polarization resistance, as low as 0.0058 Omega cm(2) was reached at 800 degrees C under air. In oxygen generator cell performance test, the electrode resistance dropped to half of the value at zero current density under an applied current density of 2.34 A cm(-2) at 700 degrees C, and on the same conditions the oxygen generator cell was continual working for more than 900 min a Faradic efficiency of similar to 100%. (c) 2007 Elsevier Ltd. All rights reserved.